Adjustable gastric banding apparatus have provided an effective and substantially less invasive alternative to gastric bypass surgery and other conventional surgical weight loss procedures. Despite the positive outcomes of invasive weight loss procedures, such as gastric bypass surgery, it has been recognized that sustained weight loss can be achieved through a laparoscopically-placed gastric band, for example, the LAP-BAND® (Allergan, Inc., Irvine, Calif.) gastric band or the LAP-BAND APO (Allergan, Inc., Irvine, Calif.) gastric band. Generally, gastric bands are placed about the cardia, or upper portion, of a patient's stomach forming a stoma that restricts the food's passage into a lower portion of the stomach. When the stoma is of an appropriate size that is restricted by a gastric band, food held in the upper portion of the stomach may provide a feeling of satiety or fullness that discourages overeating. Unlike gastric bypass procedures, gastric band apparatus are reversible and require no permanent modification to the gastrointestinal tract. An example of a gastric banding system is disclosed in Roslin, et al., U.S. Patent Pub. No. 2006/0235448, the entire disclosure of which is incorporated herein by this specific reference.
These gastric banding systems may include components such as a gastric band, an access port, fluid reservoirs and tubing to connect the various aforementioned components. Typically, these implantable components can contain or carry fluid at pressures up to about 12 psi, and are constructed out of special grades of silicone rubber for biocompatibility reasons. Metal or plastic barbed connectors are used to connect these implantable components to one another or to the tubing. These barbed connectors function well with rubber parts of higher durometer (e.g., 70 Shore A durometer or higher) but suffer from a low “pull-out” force resulting in slippage and separation of the rubber part from the barbed connected for lower durometer rubber components. This connection issue has traditionally been addressed by a number of techniques such as using an adhesive to secure the joint, overmolding the rubber on top of the hard connector to create a stronger rubber-to-connector bond, using a screw geometry or a barbed connector against the high durometer rubber, or compression fitting.
However such approaches have various drawbacks. For example, using an adhesive is undesirable due to the difficulties in controlling the amount delivered and the degree of cure for proper strength. Moreover, the adhesive might not be biocompatible.
Employing overmolding is also problematic as it is expensive and requires a metal insert which may agitate the surrounding internal organs of the patient.
Adding a screw geometry increases the cost of the system and fails to guarantee a fluid-tight seal under pressure. In addition, the rubber requires higher durometer materials due to the required structural rigidity.
Using a barbed connector also adds cost and complexity, in addition to the above-discussed agitation possibility of internal organs due to the rigidity of the materials. Furthermore, the barbed connector may still be limited for use with only high durometer rubbers since the rubber-connector contact might not generate enough resistance against a pull-out force when using a softer rubber. Fatigue-stresses at the rubber-connector junction would also remain an issue under this approach.
Compression fittings are bulky, expensive and hard to attach during a laproscopic surgical procedure.
Fusco, U.S. Patent Pub. No. 2009/0220176, discloses an application for filling polyethylene bags for the food industry, which is tangentially related in that it is also geared towards sealing. However, the system of Fusco as illustrated in FIG. 1 does not appear usable in a human body. Furthermore, the system of Fusco is structurally and functionally different than the present invention.
As a result, none of these options are particularly attractive in effectively connecting two rubber components.
Accordingly, what is needed is a connection technique that creates a reliable seal against fluid leaks at typical pressures appropriate for implantation into a human body.